Abstract: For the white strong expansive soil in Guangxi Zhuang Autonomous Region of China, by using the MATLAB software programming for binary processing of soil fissure images, a linear regression relationship between fissure ratio and water content is obtained. Field test observations show that the long-term average width of fissure is about 0.005 m before the rainy season. The correlation of the water content of surface soil and fracture spacing is obtained by means of the equivalent model. Using different fracture spacings, the fracture distribution is represented according to rainfall infiltration model in fracture seepage. Based on the description of fissures, it is shown that the calculated results of stability of cut slope with infiltration are deeply influenced by fissures. The safety factor of the slope decreases greatly with sustained rainfall when the fissure ratio is high, and it also greatly decreases with the development of the atmospheric drastic influence depth. According to the research results, some specific proposals are put forward for the cut slope of expansive soil.